High-precision characterization of scattering losses in YAG and Yb:YAG ceramics with an integrating sphere and multipass-cell

Transparent ceramic laser materials have been extensively studied for high-power laser applications, where scattering loss is a significant factor affecting laser output power. This study presents a method based on an integrating sphere combined with a multipass cell for measuring the scattering and absorption coefficients of laser materials, providing improved measurement precision. Pure YAG and Yb:YAG ceramic samples were investigated and systematically compared with pure YAG and Yb:YAG single crystals with the same Yb 3+ doping concentration. Specifically, the scattering coefficients at 1064 nm were measured to be 0.0046 cm −1 for YAG ceramic and 0.0093 cm −1 for Yb:YAG ceramic, while the corresponding absorption coefficients were 0.0267 cm −1 and 0.0221 cm −1 , respectively, which are close to those of the single crystals. Furthermore, overall optical quality and wavefront distortion were analyzed using a Shack-Hartmann wavefront sensor. The proposed method increases the effective optical interaction length, enhances the detectable loss signal, and improves measurement reliability, providing a practical approach for characterizing scattering and absorption losses in low-loss laser materials.